The present invention relates to a method and apparatus for minimizing electro-magnetic interference and more particularly to a coupler for reliably coupling a conductive housing of an electronic device to a bulkhead via a low impedance path to reduce EMI emissions.
It is desirable to minimize electro-magnetic interference (EMI) emanating from electronic devices to prevent interference with other electronic devices. In this regard, The Federal Communications Commission has promulgated standards which govern acceptable levels of EMI. Compliance with such standards has been difficult to achieve in certain applications. More specifically, while it is understood that EMI may be reduced through the use of appropriate shielding techniques, the mechanical requirements for the electronic equipment in certain applications can make compliance with the applicable standards problematic.
For example, in telecommunications equipment, such as bridges, routers and switches, transceivers are typically provided to allow for the connection of the equipment to networks via port connectors. The port connectors of the transceivers are typically accessible through openings provided within a bulkhead or chassis metalwork. Such openings have been determined to be the source of undesirable EMI emissions. In an effort to minimize EMI emissions, the electronic components of some transceivers, such as gigabit optical transceivers, are enclosed within a conductive housing. Gigabit optical transceivers are commercially available from Hewlett Packard Company, Santa Clara, Calif. 95054 and Optical Communication Products, Inc, Chatsworth, Calif. 91311 and identified as model numbers HFBR53D5EM and DTR1250MMES respectively. The above referenced optical transceivers are provided in a standard 1.times.9 Single Inline Package (SIP) configuration. In such commercially available optical transceivers, conductive members are provided which are electrically coupled to the conductive housing and extend from the housing. The conductive members are intended to be grounded to surrounding metalwork to minimize EMI emissions.
The gigabit optical transceivers include two port connectors for mating with corresponding connectors adapted for coupling to input and output cables respectively. Though efforts to ground the transceiver housings to surrounding metalwork have been made, EMI emissions at such bulkhead openings at objectionable levels have been measured notwithstanding such efforts.
Accordingly, it would be desirable to be able to reliably couple the conductive housing of a transceiver or other electrical device to a bulkhead while permitting access to connectors or controls associated with such a transceiver or device in a manner which minimizes EMI emissions in the vicinity of the bulkhead opening.